Central to the concept of mental illness is the notion that behavioral disturbances are in some sense diseases. Although clearly no longer the sole model, the disease model remains the most widely view of psychopathology.

Blaney (1975) suggests that there are four variations of the "medical model": 1. mental disorders are in fact diseases (i.e., they are physiologically based), 2. evidences of disorder are manifestations of an underlying condition (though it is not necessarily organic), 3. the individual has no responsibility for his behavior, 4. psychiatric symptoms can be best understood by ordering them into syndromes.

Historically, the view that mental disorders are diseases has been the most common view for about a century. From antiquity until the nineteenth century mental illness was viewed largely as a moral and religious issue. Persons with deviant behavior were considered to be malingerers or to be possessed by spirits. When the spirits were viewed as evil, exorcism or torture were used in an effort to remove their influence; alternatively, special favor was given when the spirits were viewed as benevolent.

Several ideas are integral parts of the disease model. The individual with the disorder, generally referred to as the patient, is sick. His sickness is manifested in a number of symptoms presumed to result from an underlying disease that was produced by a more or less specific cause, or etiology. Efforts to identify the etiology are termed diagnosis, and serve as a prerequisite to therapy or treatment. The illness is presumed to have a predictable course (or developmental history) andprognosis (or outcome).

In the disease model the symptoms are seen as manifestations of the underlying problem, not the disorder per se.

Since the individual is often unable to provide care for himself, providing care for the mentally ill becomes a social responsibility. For the patient there are several implications. He is not responsible for his present condition; he becomes a passive recipient of treatment; He may receive special considerations such as financial support at the cost of the state; he can become free from legal responsibility for actions but may also lose legal rights, since he is presumed to be unable to control his own behavior (Szasz, 1961). Finall, the patient is not considered able to evaluate his own problem; failure to recognize the "illness" may be taken as evidence that the person is in even worse condition than previously thought. Further, the problem which the patient presents may not be viewed as the real problem.

"Abnormality without a fixed norm is meaningless. The attempt of secular psychotherapy to admit norm's for morality and behavior has failed to work"

Many mental disorders clearly fit the medical model. General paresis, many forms of mental retardation, and the organic brain syndromes are prime examples of disorders resulting from diseases, trauma and the toxic effects of drugs and other substances. At the same time, many mental disorders so far have no known underlying disease process. Maher (1970) points out the diagnosis of mental disorders tends to be descriptive in nature, thus adding little information about etiology or prognosis of the disorders.

Some believe that the medical model made a major contribution to the elimination of earlier abusive and inhumane approaches to treatment of mentally ill persons. However, the role of the medical model in this development has been challenged; it appears that the moral treatment approach was actually responsible for this development, and the rise of the medical model was in some ways a backward step (Bockoven, 1963). A further criticism of the medical model involves its role in the development of the "not guilty by reason of insanity" plea and the movement away from responsibility and accountability for a variety of actions that transgress legal and moral standards (Szasz,1961).

While some continue to hold out for further advances from the medical model, others have given up on it in favor of newer models which they believe hold more promise for explaining those disorders not already explained in terms of the medical model.